Application Of Equivalent Load Method In Stress Analysis Of Prestressed Anchor Bolt Wind Turbine Foundation

With the increase of the service life of wind turbines,the foundation of ring-type wind turbine has gradually appeared various damages.Due to the limited anchoring effect of the base ring in the foundation,with the development of The Times,the foundation of ring-type wind turbine has gradually failed to meet the stress requirements of the wind turbine in the new era.The force transmission path of prestressed bolt wind turbine foundation is clear,which eliminates the abrupt change of foundation stiffness of plug ring-type wind turbine,and can give full play to the mechanical properties of foundation components.Therefore,it has high commercial value and broad application prospect in the field of wind power.At first,this paper based on the analysis of the prestressed anchor bolt wind turbine according to the present process of prestressed anchor bolt set is difficult to deal with contact with the concrete relations,through the analysis of unbonded prestressed steel beams straight finite element modeling,and compared the simulation results with the experimental data,demonstrates that the equivalent force system instead of the pre-stressed effect the feasibility and validity.Then,the 2.0MW prestressed anchor bolt wind turbine foundation is studied as the background.The finite element software ABAQUS is used to build the model.Based on the principle of equivalent load,the equivalent force system is used to replace the effect of prestressed anchor bolt on the foundation.On the outside of the loading condition of the size of the equivalent force system in the process of the iterative adjustment to simulate wind turbines in the running process of prestressed anchor expansion caused by the stress changes,analyzing condition and extreme conditions of normal loads displacement and stress distribution situation of the parts,and by the way of equivalent force system in reducing windward surface simulation of prestressed anchor bolt failure regularity,The stress and displacement of each component after failure of anchor bolt are studied.Results show that the equivalent load method can effectively simulate,pre-stressed anchor bolt type wind turbine base in the process of the working condition of external loads,the anchor plate,the anchor plate and the reinforcing cage is stress overall increasing trend with the increase of working load,on the basis of the condition and extreme conditions of normal loads concrete near the maximum compressive stress appears on the top of the lee side pillar.With the expansion of the failure bolts on the windward side,the maximum compressive stress of concrete increases with the increase of the number of failure bolts.Under normal working conditions,when the failure bolts reach 38,the maximum compressive stress of concrete exceeds the design value of axial compressive strength of material.The maximum mises stress showed an increasing trend and the windward side of the upper anchor plate was gradually increased in the process of extending to 38 anchor bolts.The maximum mises stress decreased with the increase of the number of failed bolts.The maximum mises stress decreased with the increase of the number of failed bolts.When the anchor bolt fails,the force exerted by the nearby anchor bolts on the foundation increases.With the increase of the number of failed anchor bolts,the maximum force exerted by the remaining anchor bolts on the foundation increases.